Resistor Value needed in MTX RT2120 amplifier

[Pioneer621]

Ok, I need the value of a resistor in an MTX RT2120 amplifier. The resistors board designation is R224.

I will provide a picture of the location of the part. You can see the badly burned resistor.

If someone has a relatively high resolution photo of the inside of an RT2120 I could probably get the value of the resistor like that, as long as I can see the color bands ok.

I am not exactly sure what happened to this amp, but there are several burned traces & it looks as though the RCA shields may have made contact with +12v at sometime, however I am not sure. I now one of the speaker wires of one of the rear 6x9’s it was powering was pulled off the speaker & may have shorted in the trunk. This amp was setup running both the front & rear speakers at I think if I am not mistaken 2-Ohms per channel.

I also found a shorted diode at D92, which is a 1N4001.

The following is what I know of the amps history & problems from what I was told (read it if you want to):

This is my cousins amp (I gave him this amp a few years ago & I tested it thoroughly before giving it to him & all worked well, it has also been in use until recently) & when he was over here the other day he mentioned his stereo had no sound at all & said he needed a fuse for his amp, when I realized it was the fuse built in to the amp I told him that, that being blown sounded like more of a problem then just a fuse. He told me the fuse blew once before a while back & he replaced it & it worked for a while then it blew again, & this time he could not change the fuse as part of the old fuse was stuck in the holder. It uses an ATO style 20-amp fuse.

Upon inspecting it in his trunk I could see the part of the old fuse stuck in the holder & the holder looked like it started melting lightly. The amp even kind of smelled like burnt parts. I figured I’d try it & see what it was doing so I held a new fuse in place since it could not be inserted all the way in & the amp seems to produce audio. I figured I better open it up to check it out & would need to anyway, to fix the fuse holder. As I suspected from the fuse blowing, I seen some burnt up parts & traces. We went ahead & just wired the speakers up to the head unit, not quite as loud, but I don’t think he really cares, either way I will fix the MTX amp incase he wants to use it again.

His amp just lies on his trunk floor with wires everywhere & stuff gets placed on top of them, etc. so the environment was asking for problems.

Thanks for reading & for any help you can give!


Here is the picture of the burnt resistor I need the value of:



Here are some of the other images of the burned traces:









You can see the 1N4001 diode (the black diode with the silver band) that is shorted in this photo:




Here are a couple pictures of the fuse holder damage & over heated solder connection:

[gisewhcs]

I'm not so familiar with MTX amps, but isn't there an R124 in the other channel?
Or ist that one also burnt?
That will be most probably the same.

[Pioneer621]

Originally Posted by gisewhcs

I'm not so familiar with MTX amps, but isn't there an R124 in the other channel?
Or ist that one also burnt?
That will be most probably the same.

gisewhcs,

Thank you for the fast reply!

Yeah, I know what you are saying & have worked on amps before with the left & right channels labeled like that, which may be the case with this one.

I guess I was going for the easy way out & hoping someone else could tell me the value of that resistor as it is the only unrecognizable burnt up part & I definitely would like to replace it before I start troubleshooting further.

What kind of makes it hard in this MTX amp is a lot of the board designation numbers are UNDER the parts & it’s hard to see what it is unless you lift it out of circuit which makes it a little more difficult if, not all of the parts are like that, but quite a few anyway.

Thank you again for the quick reply! Looks like I may have to start tracing the circuits & see where they take me. If only MTX would give out the schematics to there old amplifiers!

[joselorenzo]

[Pioneer621]

Originally Posted by joselorenzo

joselorenzo,

Thanks so much for the picture, exactly what I was looking for!

If I am looking at it right (which for some reason I am still terrible with the 5-Band resistors) it appears to be a 1-Ohm 1% resistor.

If I am looking at it wrong someone please correct me.

I greatly thank everyone for the help! Much appreciated!

[joselorenzo]

1 ohm is correct

[Pioneer621]

Originally Posted by joselorenzo

1 ohm is correct

Thats what I thought, but figured I would make sure! Thanks a bunch my friend!